Insulation and air sealing for Webster Groves homes: attics, crawl spaces, rim joists and walls, starting with a free assessment of the R-value you actually have. The typical home here dates to the early-1950s, and 35% of its 9,921 homes went up before 1940.
Webster Groves runs to about 5.9 square miles and roughly 24,010 people. It sits about 10 miles southwest of downtown St. Louis. That is roughly 9,921 housing units. The community dates back to 1896. We cover ZIP code 63119.
Our job history shows nothing in Webster Groves so far. Plenty of sites will show you a number here anyway.
The typical home in Webster Groves dates to around the early-1950s. Postwar building here often meant three or four inches of fiberglass and no attempt at air sealing. If nobody has touched it since, that is what is still up there.
Developers marketed the original Webster Park subdivision in 1892 as the 'Queen of the Suburbs', and housing here is predominantly prewar and immediate-postwar single-family homes on tree-lined streets.
We work across Webster Groves rather than one corner of it — Webster Park, Tuxedo Park, Old Orchard, Selma and North Webster included. Construction and vintage change between them, sometimes by thirty years and a whole different framing method, which decides whether a wall can be dense-packed at all.
Formed in 1896 from the merger of five communities: Webster, Old Orchard, Webster Park, Tuxedo Park, and Selma; North Webster was a historic Black community within the city.
The Census Bureau estimates 9,921 homes in Webster Groves. 3,479 of them (35%) went up before 1940 — the 4th-highest share of pre-1940 housing among the 44 places on this site. More of today's homes date from before 1940 than from any single decade since, and 80% predate 1980. For St. Louis County as a whole the pre-1940 share is 10%, so Webster Groves sits above it.
Of 9,446 occupied homes, 79% heat with utility gas and 20% with electricity. Electric heat here is less common than across the county (23%), and ranks 39th of 44 on this site. That is why the assessment asks how the house is heated: the fuel and the name on the utility bill decide which program, if any, can pay toward the work.
76% of occupied homes are owner-occupied and 79% of all homes are single-family detached houses. On a housing mix like this, the likely starting points are wall insulation for walls built empty and a vermiculite check before anything is disturbed.
| Built | Homes | Share | |
|---|---|---|---|
| Before 1940 | 3,479 | 35% | |
| 1940s | 1,126 | 11% | |
| 1950s | 2,154 | 22% | |
| 1960s | 698 | 7% | |
| 1970s | 528 | 5% | |
| 1980s | 680 | 7% | |
| 1990s | 719 | 7% | |
| 2000s | 219 | 2% | |
| 2010s | 212 | 2% | |
| 2020 or later | 106 | 1% |
9,921 homes, Census ACS 2020–2024 (B25034, B25040, B25003); 9,446 occupied.
3,380 of Webster Groves' 9,921 homes (34%) date from 1950 through 1979. The leaks in houses of that era repeat: nothing over the top plates, wire and pipe holes left open, an unsealed hatch, a bath fan venting into the attic, and in ranches and split-levels, heat lost at the garage ceiling and over cantilevered floors. Sealing the plates, holes and fans comes before any more fiber, and it is usually a day's work, not a renovation.
Webster Groves does not publish the energy code edition it enforces, so this page does not name one. The city's own permits page lists the codes it has adopted as the 2015 International Building, Existing Building, Residential, Fire, Mechanical, Plumbing and Property Maintenance codes plus the 2014 National Electrical Code. No energy code is named on that list. The State of Missouri's building-codes-by-city list lists Webster Groves as 2015 IECC with a 2009 IRC, which conflicts with the city's own list. Across this metro the adopted editions run from the 2015 IECC to the 2024 IECC, and several jurisdictions have no energy code at all, which is a wide spread. Ask which one your contractor is building to.
There is no published answer for Webster Groves. Neither the permit-required list nor the exemption list mentions insulation or air sealing at all. The city's permit page and FAQ name the projects that need permits, including interior renovation permits for kitchen and bath remodeling, exterior building permits for decks, accessory structure permits for any shed, plumbing permits for water heater replacement and excavation permits for right-of-way work. Insulation, air sealing and weatherization are not named. That silence is not permission and it is not a prohibition. We settle it with a phone call before the crew is scheduled.
The published number is 314-963-5300. The department page is here.
Permitting is on us, not on you.
Most Webster Groves addresses are Ameren Missouri electric customers, and Ameren Missouri pays toward insulation through Pay As You Save: $0.20 per square foot on the attic and $0.06 per square foot on air sealing in the 2026 program year, with the rest of the cost recovered through the electric bill. It counts only when the attic is at R-20 or below beforehand and R-38 or more afterward, when air sealing cuts measured leakage by 20 percent, and when the household has lived there for the past year; for income-eligible households, CommunitySavers can include attic insulation at no charge. Income-qualified households can apply to Community Action Agency of St. Louis County (CAASTLC) (314-863-0015) for free weatherization instead. The St. Louis County page and the rebate guide carry the full rules.
Every layer of an insulated attic, explained
Webster Groves borders Shrewsbury, Maplewood, Brentwood, Rock Hill, Glendale and Oakland. These are the ones we also cover, each with its own energy code and permit rule:
Elsewhere in St. Louis County we also cover:
Missouri sets none of this at state level. Across the 7 places in this table there are 3 different adopted editions (2015 IECC, 2021 IECC and 2024 IECC), and 1 of the 7 publishes a permit rule for insulation.
| City | Energy code | Attic R required | Permit to insulate | Building dept. |
|---|---|---|---|---|
| Webster Groves | Not published | — | Not published | 314-963-5300 |
| Brentwood | 2024 IECC | R-49 | Not published | 314-963-8602 |
| Affton | 2015 IECC | R-49 | Not for an attic top-up | 314-615-5184 |
| Ballwin | Not published | — | Not published | 636-227-2129 |
| Chesterfield | Not published | — | Not published | 636-537-4000 |
| Clayton | 2021 IECC | R-60 | Not published | 314-290-8463 |
| Creve Coeur | 2015 IECC | R-49 | Not published | 314-872-2500 |
All 21 St. Louis County jurisdictions side by side →
Webster Groves does not publish the energy code edition it enforces, so we do not state a required figure here. The Department of Energy recommends R60 for an uninsulated attic in this climate zone and R49 where there are already a few inches.
Webster Groves has not published a rule for it; the building department at 314-963-5300 is called before the job starts.
Ameren Missouri's Pay As You Save: $0.20 per square foot for an attic starting at R-20 or below and $0.06 per square foot for air sealing in 2026, with the balance on the electric bill. The federal 25C credit ended for work placed in service after December 31, 2025.
The typical home in Webster Groves dates to around the early-1950s; the Census Bureau's 2020-2024 median year built is 1952. Of its 9,921 homes, 35% went up before 1940 and 5% in 2000 or later. That is a median across the whole place, so your own house may be older or newer.
Code and permit facts checked September 10, 2026, rebates October 24, 2026; housing: Census ACS 2020–2024. Sources: webstergrovesmo.gov (2, 3, 4, 5) · data.mo.gov · en.wikipedia.org · city-data.com · ameren.com (2, 3, 4) · energystar.gov · data.census.gov. These change; confirm with the building department at 314-963-5300 or your electric utility first.
Free assessment, measured at the hatch, with the photographs and the number in writing.
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